class Solution(object):
    def twoSum(self, numbers, target):
        """
        :type numbers: List[int]
        :type target: int
        :rtype: List[int]
        """
        begin = 0
        end = len(numbers)-1
        while True:
            sum = numbers[begin] + numbers[end]
            if sum>target: end-=1
            elif sum<target: begin+=1
            else: return [begin+1, end+1]
